1. Technical Field
The present application relates to a light-emitting diode device, and in particular to a light-emitting diode device with high light extraction efficiency.
2. Description of the Related Art
Different from the conventional lighting, the emitting principles and structures of light-emitting diode devices (LEDs) have advantages such as low power consumption, long operational life, without warming-time, quick response, small volume, shockproof and high productivity. LEDs have been widely used in applications and are easily to form small or array devices, such as the optical display devices, laser diodes, traffic lights, data storage devices, communication devices and medical devices.
Referring to FIG. 1A and FIG. 1B, a conventional light-emitting diode device 1 comprises a transparent substrate 10, a plurality of light-emitting diode units 12 extended two dimensionally and formed close to each other on the transparent substrate 10. Each stack 120 of the light-emitting diode units 12 comprises a first semiconductor layer 121, an active layer 122, and a second semiconductor layer 123. Because the transparent substrate 10 is not conductive, gaps 14 formed by etching between the light-emitting diode epitaxial stacks 120 can insulate the light-emitting diode units 12 from each other. Next, partial exposed area is exposed by etching the light-emitting diode epitaxial stacks 120 to the first semiconductor layer 121. Then, forming a conductive connecting structure 19 including a first electrode 18 and a second electrode 16 on the exposed area of the first semiconductor layer 121 of the light-emitting diode epitaxial stack 120 and the second semiconductor layer 123 of adjacent light-emitting diode epitaxial stack 120 respectively. The first electrode 18 and the second electrode 16 respectively comprise a first electrode extension 180 and a second electrode extension 160 formed on the first semiconductor layer 121 of the light-emitting diode epitaxial stack 120 and the second semiconductor layer 123 of adjacent light-emitting diode epitaxial stack 120 to help current spread evenly into the semiconductor layer. The conductive connecting structure 19 selectively connects the second semiconductor layer 123 and the first semiconductor layer 121 of adjacent light-emitting diode units 12 to form serial circuits or parallel circuits between the light-emitting diode units 12. There can be air or an insulating layer 13 beneath the conductive connecting structures 19 where in the insulating layer 13 is formed on the partial surface of epitaxial stacks of the light-emitting diode unit 12 and the space between the epitaxial stacks of adjacent light-emitting diode unit 12 by CVD, PVD, sputtering and so on before forming the conductive connecting structures 19 to protect the epitaxial stacks and insulate the adjacent light-emitting diode units. The material of the insulating layer 13 comprises Al2O3, SiO2, AlN, SiNx, TiO2, Ta2O5, or the combination thereof.
However, when the conductive connecting structure 19 electrically connects the light-emitting diode units 12, because the depth of the gap 14 between the light-emitting units 12 is large, it is easy to cause bad connection or broken line when forming conductive connecting structures 19, and the yield of the devices is influenced therefore.
Furthermore, the light-emitting diode device 1 mentioned above can connect to other devices to form a light-emitting apparatus. FIG. 2 is a schematic diagram illustrated the conventional light-emitting apparatus. As shown in FIG. 2, a light-emitting apparatus 100 comprises a sub-mount 110 comprising a circuit 101, and the light-emitting diode device 1 is fixed onto the sub-mount 110; an electrical connection structure 104 electrically connects a first electrode pad 16′ and a second electrode pad 18′ of the light-emitting diode device 1 and the circuit 101 of the sub-mount 110. The sub-mount 110 can be the lead frame or the large mounting substrate which is convenient for the circuit layout of the light-emitting diode device 100 and suitable for heat dissipation. The electrical connection structure 104 can be the bonding wires or other connecting structures